I'd salt it overnight (get some smoked Maldon), rubbing off the excess salt and then immersing into pre-warmed fat. Carefully!

I'd start off with the fat at 150C in a pre-warmed oven, immerse the meat and then drop the temperature to 125C for an hour or two, then down again to 100C ish for another 6 hours. The meat must be fully immersed.

The fat should still be usable - it will not have oxidised in this time but you'll probably want to strain it.